TABLE OF CONTENTS In modeling noise in solid-state devices, we must address a number of matters. First, of course, is the nature of the sources and their location in the equivalent circuit or black-box model of a solid-state device. This is closely allied with the nature of the device's circuit model. The second is the scaling of the sources and their correlations with frequency and, in many cases, control voltages or currents. Finally, we usually must deal separately with low-frequency noise (1/ f and burst noise) and broadband, high-frequency noise, which have distinctly different physical sources and characteristics.
Perhaps because of the difficulty of these questions, few modern models in widespread use address them completely. At this writing, the RF and microwave industry still depends heavily on models introduced in the SPICE circuit simulator, which dates from the mid-1970s. In this chapter, we devote considerable effort to their description. Some of these models, such as the Schottky diode noise model, are surprisingly good; others less so.
It is important to recognize that SPICE does not include nonlinear noise analysis. Thus, the noise models developed for SPICE were originally intended for linear noise analysis at a bias point determined by SPICE's dc analysis. Their use for nonlinear noise analysis depends on an assumption that such static models are valid for dynamic applications as well.
The simplest noisy element to model is a resistor. We saw, in Section 2.3.1, that a resistor generated white thermal noise and...
